OK - I've tried embedding some code using Upfront... and it's only half working!
Test page: http://canoearoundbritain.com/location/
I dragged the "Code" element into the main Region and pasted the "basic usage" embed code from here:
As directed, I then substituted the Page Feed ID from here:
I've tried different Google Maps API Keys in the "Upfront" dashboard... and can get an outline box showing that some part of what I've done is working.... but we're still not seeing the map data!